JP2009272207A - Sealed battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealed battery with its charge and discharge cycle life made longer than that of a conventional sealed battery. <P>SOLUTION: An internal terminal 8 connected with an external terminal 5 is connected with a tab 9 extended from a power generation element 3. The external terminal 5, the inner terminal 8 and the power generation element 3 are fixed through an upper part gasket 6 and a lower part gasket 7 at an upper part and a lower part of a lid 4 inside a battery case 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sealed battery, and more particularly to its internal structure.

  Various types of batteries are used as power sources for small electronic devices, and small, large-capacity sealed batteries are used as power sources for mobile phones, laptop computers, etc. A sealed battery using a non-aqueous electrolyte of the battery is used. However, in addition to the demand for further improvement of the energy density of the sealed battery, the number of times of charge / discharge when using the sealed battery, that is, the demand for extending the life of the charge / discharge cycle is also increasing.

  4A and 4B are explanatory views of the structure of a conventional sealed battery. FIG. 4A is a top view of the sealed battery, FIG. 4B is a sectional view taken along the line DD, and FIG. 4C is a header. It is a perspective view of a part. The sealed battery 101 includes a battery case 2, a power generation element 3, a lid 4, an external terminal 5, an upper gasket 6, a lower gasket 7, an internal terminal 8, a tab 9 and an insulating plate 10.

  The sealed battery 101 includes a battery case 2 made of aluminum or an alloy thereof, a positive electrode (not shown) and a negative electrode (not shown) stacked on a battery case 2 via a separator (not shown), wound and molded. 3 and the insulating plate 10, and the plate-like tab 9 extended from the power generation element 3 is electrically connected to the internal terminal 8 joined to the lid 4 via the lower gasket 7, and the external terminal 5 is connected. The upper gasket 6, the lid 4 and the lower gasket 7 are electrically connected to the internal terminal 8, and the header portion 11 including the lid 4, the external terminal 5, the upper gasket 6 and the lower gasket 7 is connected to the battery case 2. Then, the header 11 and the battery case 2 are laser welded.

  In order to improve the energy density of the sealed battery and prolong the life of the charge / discharge cycle, for example, in Patent Document 1, an insulating plate is arranged to suppress an internal short circuit between the power generation element, the lid, and the battery case. It has been proposed to do. The sealed battery containing the insulating plate is effective in preventing the inner wall and lid of the battery case and the power generation elements from being short-circuited inside the sealed battery.

JP 200431263 A

  In order to extend the life of the charge / discharge cycle of the sealed battery, it is necessary to reduce the volume of the insulator that does not contribute to the battery capacity and secure the volume for injecting the electrolyte. However, the conventional sealed battery has a limit in reducing the volume of the insulator due to the structure using the insulating plate.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a sealed battery that extends the charge / discharge cycle of the sealed battery further than the conventional sealed battery.

  According to the present invention, a power generation element in which a positive electrode and a negative electrode are wound around a winding axis through a separator in a battery case having an opening so that the winding axis is perpendicular to the opening surface. A sealed battery that is housed and sealed by fitting a lid to the opening of the battery case, and an internal terminal connected to an external terminal is connected to a tab extended from the power generation element, The external terminal is joined to the lid via an upper gasket, the internal terminal is joined to the lid via a lower gasket, the external terminal and the internal terminal are electrically connected, and the lower gasket is A sealed battery having a side surface extending in a direction of the power generation element between the battery case and the tab.

  Further, the present invention is the sealed battery, wherein the lower gasket has a protrusion extending in the thickness direction of the sealed battery near the tip of the side surface.

  Moreover, this invention is a sealed battery characterized by the thickness of the said lower gasket being 0.3-0.8 mm.

  Further, the present invention is the sealed battery characterized in that the length of the protrusion of the lower gasket is 1/3 to 1/2 of the inner dimension of the battery case in the thickness direction of the sealed battery. .

  The present invention is also a sealed battery characterized in that a side surface of the lower gasket is formed to cover the periphery of the internal terminal and the tab.

  According to the present invention, the lower gasket inside the battery covers the tab so that the tab extended from the power generation element and the inner wall of the battery case do not come into contact with each other and the protrusion extends in the thickness direction of the sealed battery. In the battery case, an insulating plate housed in a conventional sealed battery is used by preventing the power generation element from freely moving in the longitudinal direction (vertical direction) of the sealed battery from the lower gasket. Therefore, it is possible to provide a sealed battery that can inject a volume of an electrolyte solution that reduces the amount of insulation that does not contribute to the battery capacity, and that can extend the life of the charge / discharge cycle of the sealed battery. .

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory view of the structure of a sealed battery according to a first embodiment of the present invention, FIG. 1 (a) is a top view of the sealed battery, and FIG. 1 (b) is a cross section taken along the line AA. FIG. 1 and FIG. 1C are perspective views of the header portion. The sealed battery 1 includes a battery case 2, a power generation element 3, a lid 4, an external terminal 5, an upper gasket 6, a lower gasket 7, an internal terminal 8, and a tab 9.

  The sealed battery 1 includes a battery case 2 made of aluminum or an alloy thereof, and a power generation element formed by laminating a positive electrode (not shown) and a negative electrode (not shown) via a separator (not shown) and winding them. 3 and a metal plate-like tab 9 extended from the power generation element 3, an insulating lower gasket such as polyphenylene sulfide resin (PPS) or tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) 7 is electrically connected to the metal internal terminal 8 joined to the metal lid body 4 through 7, and the external terminal 5 electrically connected to the internal terminal 8 is connected to an insulating upper gasket such as PFA. 6 and the lower gasket 7 are connected to the lid 4, and the header portion 11 including the lid 4, the external terminal 5, the upper gasket 6, and the lower gasket 7 is fitted into the battery case 2, The Dda portion 11 and the battery case 2 are laser welded.

  In the sealed battery 1, a positive electrode and a negative electrode are stacked in a rectangular battery case 2 through a separator, wound flatly around a winding axis, and further pressed to form the shape of the battery case 2. The power generation element 3 flattened so as to match is accommodated so that the winding axis is perpendicular to the opening of the battery case 2, and the tab 9, the internal terminal 8, and the lower gasket 7 are accommodated and sealed with the lid 4. It has a structure to do.

  An insulating lower gasket 7 is provided between the conductive tab 9 and the conductive battery case 2 or between the conductive tab 9 and the conductive lid 4, and the conductive tab 9 is a conductive battery case. 2 or the conductive lid 9 is arranged so as to be isolated from the conductive lid 4 so that the conductive tab 9 does not contact with the conductive battery case 2 or the conductive lid 4 to be short-circuited. Has been. In order to prevent a short circuit, since the side surface of the U-shaped lower gasket 7 is extended to the vicinity of the power generation element 3, the side surface of the lower gasket 7 is also regulated so that the power generation element 3 does not move greatly.

  Further, the outer dimensions of the prismatic lower gasket 7 only need to be smaller than that of the lid 4, and the width of the lower gasket 7 is 0.5 to 1. mm less than the internal terminals 8 so that the lid 4 and the internal terminals 8 are not short-circuited. A length of about 0 mm is sufficient.

  FIG. 2 is an explanatory view of the structure of a sealed battery according to a second embodiment of the present invention, FIG. 2 (a) is a top view of the sealed battery, and FIG. 2 (b) is a cross section taken along line BB. FIG. 2 and FIG. 2C are perspective views of the header portion. The sealed battery 1 includes a battery case 2, a power generation element 3, a lid 4, an external terminal 5, an upper gasket 6, a lower gasket 7, an internal terminal 8, and a tab 9.

  The sealed battery 1 has a positive electrode (not shown) and a negative electrode (not shown) stacked on a battery case 2 made of aluminum or an alloy thereof via a separator (not shown), and the winding axis is the center. The wound power generation element 3 is wound and the metal plate-like tab 9 extended from the power generation element 3 is replaced with polyphenylene sulfide resin (PPS) or tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA). A metal internal terminal 8 joined to the metal lid 4 via an insulating lower gasket 7 is electrically connected, and the external terminal 5 electrically connected to the internal terminal 8 is connected to the PFA. A battery case is connected to the lid 4 through an insulating upper gasket 6 and a lower gasket 7 and the header portion 11 comprising the lid 4, the external terminal 5, the upper gasket 6 and the lower gasket 7. After fitted into, and laser welding the header portion 11 and the battery case 2.

  In the sealed battery 1, a positive electrode and a negative electrode are stacked in a rectangular battery case 2 through a separator and wound flat, and then pressed to be flattened so as to match the shape of the battery case 2. The power generation element 3, the tab 9, the internal terminal 8, and the lower gasket 7 are accommodated and sealed with the lid 4.

  The structure of the sealed battery according to the second embodiment of the present invention is the same as the structure of the sealed battery according to the first embodiment of the present invention, but the lower gasket 7 is shown in FIG. As shown in the sectional view of FIG. 3, the lower gasket 7 on the power generation element 3 side is provided with a protrusion 71 extending in the thickness direction of the sealed battery, and the protrusion 71 is arranged in the vicinity of the power generation element 3. Thus, it is possible to prevent the power generation element 3 from moving in the direction of the lid 4 in the case of dropping or the like so as not to cause a short circuit inside the battery.

  The thickness of the lower gasket 7 is preferably 0.3 to 0.8 mm. When the thickness of the lower gasket 7 is 0.3 mm or less, when the battery case 2 and the lid 4 are welded, the lower gasket 7 made of an insulating resin material is melted and is 0.8 mm or more. This is because the volume occupied by the lower gasket 7 increases. Moreover, it is preferable that the length of the projection part 71 is 1/3 to 1/2 of the inner dimension of the battery case 2 in the thickness direction of the sealed battery. If the length of the protruding portion 71 is 1/3 or less of the inner dimension of the battery case 2, the power generation element 3 moves inside the sealed battery due to external vibration, and the length of the protruding portion 71 is that of the battery case 2. This is because the internal dimension of the battery case 2 exceeds the internal dimension of ½ or more of the internal dimension.

  An insulating lower gasket 7 is provided between the conductive tab 9 and the conductive battery case 2 or between the conductive tab 9 and the conductive lid 4, and the conductive tab 9 is a conductive battery case. 2 or the conductive lid 9 is arranged so as to be isolated from the conductive lid 4 so that the conductive tab 9 does not contact with the conductive battery case 2 or the conductive lid 4 to be short-circuited. Has been.

  Further, the outer dimensions of the prismatic lower gasket 7 only need to be smaller than that of the lid 4, and the width of the lower gasket 7 is 0.5 to 1. mm less than the internal terminals 8 so that the lid 4 and the internal terminals 8 are not short-circuited. A length of about 0 mm is sufficient.

  FIG. 3 is an explanatory view of the structure of a sealed battery according to a third embodiment of the present invention, FIG. 3 (a) is a top view of the sealed battery, and FIG. 3 (b) is a cross section taken along the line CC. FIG. 3C is a perspective view of the header portion. The sealed battery 1 includes a battery case 2, a power generation element 3, a lid 4, an external terminal 5, an upper gasket 6, a lower gasket 7, an internal terminal 8, and a tab 9.

  The sealed battery 1 has a positive electrode (not shown) and a negative electrode (not shown) stacked on a battery case 2 made of aluminum or an alloy thereof via a separator (not shown), and the winding axis is the center. The formed power generation element 3 is wound and the metal plate-like tab 9 extended from the power generation element 3 is replaced with polyphenylene sulfide resin (PPS) or tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA). A metal internal terminal 8 joined to the metal lid 4 via an insulating lower gasket 7 is electrically connected, and the external terminal 5 electrically connected to the internal terminal 8 is connected to the PFA. A battery case is connected to the lid 4 through an insulating upper gasket 6 and a lower gasket 7 and the header portion 11 comprising the lid 4, the external terminal 5, the upper gasket 6 and the lower gasket 7. After fitted into, and laser welding the header portion 11 and the battery case 2.

  In the sealed battery 1, a positive electrode and a negative electrode are stacked in a rectangular battery case 2 through a separator and wound flat, and then pressed to be flattened so as to match the shape of the battery case 2. The power generation element 3, the tab 9, the internal terminal 8, and the lower gasket 7 are accommodated and sealed with the lid 4.

  The structure of the sealed battery according to the third embodiment of the present invention is the same as the structure of the sealed battery according to the first and second embodiments of the present invention. As shown in the sectional view of (b), the lower gasket 7 on the power generation element 3 side is provided with a protrusion 71 extending in the thickness direction of the sealed battery, and the protrusion 71 is disposed in the vicinity of the power generation element 3. By adopting the structure, it is possible to prevent the power generation element 3 from moving in the direction of the lid 4 in the case of dropping or the like and prevent a short circuit from occurring inside the battery.

  In the sealed battery according to the third embodiment of the present invention, as shown in the perspective view of FIG. 3C, the side surface of the lower gasket 7 which is a surface parallel to the battery case 2 is composed of four surfaces. Each of the four surfaces is in the shape of a prism. The bottom surface has a cavity. Thereby, it can restrict | limit more firmly that the electric power generation element 3 moves to the cover body 4 direction at the time of dropping. Moreover, since the shape of the lower gasket 7 should just be the shape which surrounds the circumference | surroundings of the internal terminal 8 tab 9, it may be a polygonal column shape, a column shape, etc.

  The thickness of the lower gasket 7 is preferably 0.3 to 0.8 mm. When the thickness of the lower gasket 7 is 0.3 mm or less, when the battery case 2 and the lid 4 are welded, the lower gasket 7 made of an insulating resin material is melted and is 0.8 mm or more. This is because the volume occupied by the lower gasket 7 increases. Moreover, it is preferable that the length of the projection part 71 is 1/3 to 1/2 of the inner dimension of the battery case 2 in the thickness direction of the sealed battery. If the length of the protruding portion 71 is 1/3 or less of the inner dimension of the battery case 2, the power generation element 3 moves inside the sealed battery due to external vibration, and the length of the protruding portion 71 is that of the battery case 2. This is because the internal dimension of the battery case 2 exceeds the internal dimension of ½ or more of the internal dimension.

  An insulating lower gasket 7 is provided between the conductive tab 9 and the conductive battery case 2 or between the conductive tab 9 and the conductive lid 4, and the conductive tab 9 is a conductive battery case. 2 or the conductive lid 9 is arranged so as to be isolated from the conductive lid 4 so that the conductive tab 9 does not contact with the conductive battery case 2 or the conductive lid 4 to be short-circuited. Has been.

  Further, the outer dimensions of the prismatic lower gasket 7 only need to be smaller than that of the lid 4, and the width of the lower gasket 7 is 0.5 to 1. mm less than the internal terminals 8 so that the lid 4 and the internal terminals 8 are not short-circuited. A length of about 0 mm is sufficient. Moreover, since the shape of the lower gasket 7 should just be the shape which surrounds the circumference | surroundings of the internal terminal 8 tab 9, it may be a polygonal column shape, a column shape, etc.

  The preferred embodiments of the sealed battery according to the present invention have been described above with reference to the drawings. However, the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these are naturally within the technical scope of the present invention. Understood.

  Next, the present invention will be described in detail with specific examples.

Example 1
As shown in FIG. 1, a battery case 2 made of an aluminum alloy having a length of 38.0 mm, a width of 35.4 mm, a thickness of 4.2 mm, and a thickness of 0.2 mm is provided on a plate having a width of 4.0 mm and a thickness of 0.1 mm. A vertical sheet produced by laminating a positive electrode sheet welded with a tab and a negative electrode sheet ultrasonically welded with a tab having a width of 4 mm and a thickness of 0.1 mm through a separator of a microporous polypropylene film, and wound in a spiral shape. The power generation element 3 having a thickness of 0.5 mm, a width of 34.0 mm, and a thickness of 3.6 mm was accommodated, the tab 9 and the header portion 11 were welded, and the lid 4 was fitted to the battery case 2 and then laser-welded. After injecting the electrolyte, the inlet was sealed to produce a lithium ion battery. For the lower gasket 7 of the header portion 11, PPS having a length in the longitudinal direction of the lid 4 of 10.0 mm, a length in the vertical direction of the battery case of 1.5 mm, and a thickness of 0.3 mm was used.

(Example 2)
As shown in FIG. 2, a lithium ion battery was produced in the same manner as in Example 1 except that a protrusion 71 having a length of 1.5 mm was attached to the power generation element 3 side of the lower gasket 7.

(Example 3)
As shown in FIG. 3, a lithium ion battery was produced in the same manner as in Example 2 except that the lower gasket 7 had four surfaces perpendicular to the lid 4.

(Comparative Example 1)
As shown in FIG. 4, the lower gasket 7 uses a plate-like PPS having a wall thickness of 0.6 mm and an L-shaped protrusion 72 of 0.3 mm on the inner terminal 8 side in the center. Lithium ion is the same as in Example 1 except that a concave insulating plate 10 made of polypropylene (PP) having a height of 3.6 mm, a width of 33.8 mm, a height of 1.5 mm, and a wall thickness of 0.3 mm is accommodated between 4. A battery was produced.

  Under the conditions described above, five samples at each level were prepared. In the electrolyte solution injection process during sample preparation, the maximum injection volume that can be injected was injected. Table 1 shows the volumes of the lower gaskets 7 of Examples 1 to 3 when the volume of the lower gasket 7 and the insulating plate 10 used in Conventional Example 1 is 100%.

  In addition, a charge / discharge cycle test was performed using the prepared sample. In the cycle test, the sample was repeatedly charged and discharged under a condition of a current of 720 mA in a voltage range of 3.0 to 4.2 V in a 20 ° C. constant temperature bath. The initial discharge capacity (initial discharge capacity) was 100%, and the cycle test was terminated when the discharge capacity during the cycle test reached 70% of the initial discharge capacity. Table 2 shows the number of charge / discharge cycles that led to the end of the cycle test.

  As mentioned above, since the volume of the lower gasket 7 of Examples 1-3 when the volume of the lower gasket 7 and the insulating plate 10 is 100% is reduced to about 60% compared with the conventional example, In this way, the number of charge / discharge cycles of Examples 1 to 3 can be confirmed to be about 12% higher than that of the comparative example, and the battery life can be extended. It was.

BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing of the sealed battery which concerns on the 1st Embodiment of this invention. FIG. 1A is a top view of a sealed battery. FIG.1 (b) is sectional drawing of an AA line. FIG.1 (c) is a perspective view of a header part. Structure explanatory drawing of the sealed battery which concerns on the 2nd Embodiment of this invention. FIG. 2A is a top view of the sealed battery. FIG.2 (b) is sectional drawing of a BB line. FIG.2 (c) is a perspective view of a header part. Structure explanatory drawing of the sealed battery which concerns on the 3rd Embodiment of this invention. FIG. 3A is a top view of the sealed battery. FIG.3 (b) is sectional drawing of CC line. FIG. 3C is a perspective view of the header portion. Structure explanatory drawing of the conventional sealed battery. FIG. 4A is a top view of the sealed battery. FIG. 4B is a sectional view taken along line DD. FIG. 4C is a perspective view of the header portion.

Explanation of symbols

1,101 Sealed battery 2 Battery case 3 Power generation element 4 Lid 5 External terminal 6 Upper gasket 7 Lower gasket 8 Internal terminal 9 Tab 10 Insulating plate 11 Header part 71 Projection part 72 L-shaped projection part

Claims (5)

In a battery case having an opening, a power generation element in which a positive electrode and a negative electrode are wound around a winding axis via a separator is stored so that the winding axis is perpendicular to the opening surface, A sealed battery in which a lid is fitted and sealed in the opening of the battery case,
An internal terminal connected to an external terminal is connected to a tab extended from the power generation element;
The external terminal is joined to the lid through an upper gasket,
The internal terminal is joined to the lid through a lower gasket,
The external terminal and the internal terminal are electrically connected,
The sealed battery according to claim 1, wherein the lower gasket has a side surface extending in the direction of the power generation element between the battery case and the tab.   2. The sealed battery according to claim 1, wherein the lower gasket has a protruding portion extending in a thickness direction of the sealed battery in the vicinity of a tip portion of the side surface.   The sealed battery according to claim 1, wherein a thickness of the lower gasket is 0.3 to 0.8 mm.   The length of the protrusion part of the said lower gasket is 1/3-1/2 of the internal dimension of the battery case in the thickness direction of a sealed battery, Either of Claim 2 or Claim 3 characterized by the above-mentioned. The sealed battery according to 1.   The sealed battery according to any one of claims 1 to 4, wherein a side surface of the lower gasket has a shape covering the periphery of the internal terminal and the tab.

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